Middle Ear Prosthesis

ABSTRACT

A middle ear prosthesis comprises a body of deformable material capable of retaining different shapes. The body comprises a slotted wall defining a cavity for receiving a bone of the middle ear. The wall is deformable proximate slots in the wall between an open position for receiving the bone and a closed position wherein the body is reshaped to grasp the bone.

CROSS REFERENCE

This application is a continuation of application U.S. Ser. No.11/789,629 filed Apr. 25, 2007 which is a continuation-in-part of Ser.No. 10/976,638, filed Oct. 29, 2004, and a continuation-in-part of Ser.No. 11/428,672, filed Jul. 5, 2006, which is a continuation of U.S. Ser.No. 10/666,451, filed Sep. 19, 2003, now issued as U.S. Pat. No.7,087,081, and claims benefit of both Ser. No. 60/823,914, filed Aug.30, 2006, and Ser. No. 60/853,938, filed Oct. 24, 2006.

FIELD OF THE INVENTION

This invention relates to an ossicular prosthesis used for replacementand reconstruction and, more particularly, to a middle ear prosthesis ofa deformable material.

BACKGROUND OF THE INVENTION

Due to disease, trauma, or congenital malformation, the ossicles of themiddle ear are sometimes damaged. The delicate joint between the incusand the stapes is termed the incudo-stapedial joint (ISJ). The ISJ is acartilaginous joint having a tendency to ossify in older humans. Whenthe joint is interrupted due to erosion of the joint or the incusitself, vibrations can no longer be transmitted from the incus to thestapes. The result is a conductive hearing loss related to the disruptedossicular chain.

Medical implants have been developed to reconstruct the ossicular chainwhen a portion of the incus is missing. However, the entire incus has tobe removed and replaced with a prosthesis. This approach destroys thenatural joint between the incus and stapes and the lever function of theincus in relationship to the malleus and stapes.

One particular implant to address conditions when only the ISJ is erodedor ossified is shown in U.S. Pat. No. 5,306,299. This prosthesis is madefrom a hydroxylapatite. Particularly, the prosthesis comprises a blockof hydroxylapatite having a cylindrical cavity intersecting with aU-shaped channel. The prosthesis cannot be adjusted to conform tovarious sized incus and stapes. As such, the prosthesis must be providedin different sizes for different size ossicular chains. Because of itsmass and lack of features to stabilize its connection to the incus andstapes, it is possible for the prosthesis to migrate and extrude throughthe ear drum over a period of time. Concerns over the weight of theceramic material and the overall mass of the prosthesis have beenraised. Also, the hydroxylapatite material is inherently fragile, proneto breakage and cannot be easily modified to custom fit the incus orstapes head.

An alternative ISJ prosthesis is disclosed in U.S. Pat. No. 5,514,177.This prosthesis is formed of composite construction using pieces ofdifferent materials secured together such as by welding.

Certain ossicular prosthetics require that they be manually crimped tothe bone. Fixating or crimping an ossicular prosthesis to bone can bedifficult due to problems with prosthesis stability, surgical exposure,appropriate clamping, etc. It is desirable to have a prosthesis that is“self-crimping”. Ideally, the self crimping prosthesis should be lowprofile and provide secure, stable fixation. It should also be easy toapply without damaging the ossicles and apply a small amount of pressureto the ossicles so as to minimize the potential for pressure necrosis.

U.S. Pat. Nos. 6,197,060 and 6,554,861 describe various ossicularprostheses that include a shape memory wire or ribbon reversely turnedon itself to form an open-ended bight. The bight is opened with a tooland then automatically closed and crimped about an ossicle upon theapplication of a signal such as heat. However, such a bight structure isineffective for coupling various ossicular bones together, eitherbecause of the anatomy or because of the lack of the stability provided.

The present invention is directed to improvements in middle earprosthetics.

SUMMARY OF THE INVENTION

In accordance with one aspect of the invention, there is provided anadjustable middle ear prosthesis.

Broadly, there is disclosed in accordance with one aspect of theinvention, an adjustable middle ear prosthesis comprising a unitary bodyof deformable material capable of retaining different shapes. The bodycan be reshaped to fit to and retain ossicular bones, such as the stapesand the incus, in a desired relationship. The body is preferably made ofa malleable titanium, such as soft unalloyed titanium, or a shape memorymaterial such as nickel-titanium or a polymer.

In one embodiment of the invention, the body comprises a generallytubular first cavity for receiving a head of a stapes and an elongatesecond cavity extending generally perpendicular to the generally tubularfirst cavity for receiving an incus. The body comprises a collardefining the generally tubular first cavity. The collar may have alongitudinally extending through slot, and may include a pair ofopposite longitudinally extending through slots. The body comprises agenerally semi-cylindrical wall connected to opposite parallel wallshaving inwardly extending flanges defining the elongate second cavity.The semi-cylindrical wall may include a keyhole slot. The oppositeparallel walls may be connected to the semi-cylindrical wall by bridgesto define elongate slots between the opposite parallel walls and thesemi-cylindrical wall. The flanges are spaced apart to define a cavityslot. The opposite parallel walls with flanges extending inwardtherefrom together define a generally U-shaped wall. The U-shaped walland semi-cylindrical wall together define the second cavity extendinggenerally perpendicular to the first cavity for receiving an incus.

According to a second embodiment of the invention, an ISJ prosthesis isprovided including first and second slotted tubular portionsperpendicularly arranged relative to each other. The first slottedtubular portion includes one or more wall portions that are opened andthe second slotted tubular portion includes fingers that are opened. Thewall portions and fingers are deformed about the stapes and incus,preferably by the application of heat, to stably hold the stapes andincus in the desired anatomical relationship.

According to third embodiment of the, invention, an angular pistonprosthesis is provided in which a slotted tubular portion is provided ona rod element. The slotted tubular portion includes one or more armsthat can be deformed about the incus, such as by application of heat,and the rod element is sized in length to extend from the incus to thestapes footplate or oval window.

According to a fourth embodiment of the invention, a partial ossicularreplacement prosthesis (PORP) is provided. The prostheses includes aninverted cup defining a cavity for the head of the stapes, a shaftextending from the cup, and a disc at the end of the shaft for placementagainst the tympanic membrane. The disc may be longitudinallydisplaceable on the shaft to adjust the length of the prosthesis.According to the invention, the cup includes at least one slot definedin a wall thereof permitting the circumference of the wall to bedeformed into an open position to facilitate receiving the head of thestapes and then closed upon application of heat to retain the stapes.

According to a fifth embodiment of the invention, another PORP isprovided including a shaft, a disc at one end, and a mount for engagingthe head or capitulum of the stapes at the other end. The mount includestwo side walls each provided with a longitudinal recess in which toreceive the arch of the stapes. Between the side walls an anchor tab isprovided and has a length sufficient to extend across the diameter ofthe mount. The tab is deformed open to permit the arch of the stapesaccess into the recesses. Then, upon application of heat to the tab, thetab automatically deforms to bend through the arch and under thecapitulum to lock the stapes to the PORP.

Further features and advantages of the invention will be readilyapparent from the specification and from the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective, partial cross-section of the anatomy of an earshowing a normal ossicular chain;

FIG. 2 is a perspective view of an adjustable incudo-stapedial joint(ISJ) prosthesis in accordance with the invention;

FIG. 3 is a top plan view of the ISJ prosthesis of FIG. 2;

FIG. 4 is a bottom plan view of the ISJ prosthesis of FIG. 2;

FIG. 5 is a front elevation view of the ISJ prosthesis of FIG. 2;

FIG. 6 is a rear elevation view of the ISJ prosthesis of FIG. 2;

FIG. 7 is a side elevation view of the ISJ prosthesis of FIG. 2;

FIG. 8 is a perspective view illustrating the ISJ prosthesis inaccordance with the invention implanted in a human ear;

FIG. 9 is an upper front perspective view of an ISJ prosthesis inaccordance with an alternative embodiment of the invention;

FIG. 10 is an upper rear perspective view of the ISJ prosthesis of FIG.9;

FIG. 11 is a lower front perspective view of the ISJ prosthesis of FIG.9;

FIG. 12 is a lower rear perspective view of the ISJ prosthesis of FIG.9;

FIGS. 13-16 correspond to FIGS. 9-12, respectively, showing the ISJprosthesis deformed for packaging and pre-implantation;

FIG. 17 is an upper rear perspective view of an angular pistonprosthesis in accordance with the invention;

FIGS. 18 and 19 are perspective views of an ossicular replacementprosthesis with a cup portion shown as machined;

FIG. 20 is a perspective view similar to FIG. 18 showing the cup in ashape set position;

FIG. 21 is a perspective view similar to that of FIGS. 18 and 20,showing the cup in an open position for packaging and pre-implantation;

FIG. 22 is a side elevation view of a partial ossicular replacementprosthesis with a locking arm in a set position; and

FIG. 23 is an elevation view similar to FIG. 22 showing the locking armin the open position for packaging and pre-implantation.

DETAILED DESCRIPTION OF THE INVENTION

Referring initially to FIG. 1, a human ear 10 includes an external orouter ear 12, a middle ear 14 and an inner ear 16. A tympanic membrane18, also called the ear drum, separates the outer ear 12 from the middleear 14. The middle ear 14 includes an ossicular chain 20 comprisingthree small bones that are connected and transmit the sound waves fromthe ear drum 18 to the inner ear 16. The three small bones are calledthe malleus 22, the incus 24, and the stapes 26. The stapes 26 includesa loop or arch 28 connected to a footplate 30. A head (capitulum) 32 atthe top of the arch 28 connects to the lenticular process of the incus24 at an incudo-stapedial joint (ISJ) 34.

In accordance with the invention, an ISJ prosthesis 40, see FIGS. 2-7,is used when only the ISJ and possibly a short segment of the distalaspect of the long arm of the incus is eroded or ossified. In accordancewith this disclosed aspect of the invention, the ISJ prosthesis 40contains a series of slots enabling the prosthesis to be adjusted inmultiple planes to provide a custom fit to either the incus 24 or thestapes head 32.

The ISJ prosthesis 40 is of unitary construction manufactured, such asby machining, to form a one-piece deformable, malleable metal body 42.For ease of description herein, the body 42 is described referring tothe left-most part in FIGS. 3 and 4 as the front and the right-most partin FIGS. 3 and 4 as the rear. It should be understood, however, thatthese relative terms are for reference only in describing the device anddo not describe any particular characteristics of the prosthesis 40.

The body 42 comprises a generally semi-cylindrical wall 44 having a topend 46 and a bottom end 48. A rounded notch 50 is provided proximate thetop end 46. A keyhole slot 52 is provided through the semi-cylindricalwall 44 originating at the bottom end 48.

The semi-cylindrical wall 44 is connected to opposite arcuate wallportions 54 and 56 at its bottom end 48. The arcuate wall portions 54and 56 have respective distal edges 58 and 60 spaced apart to define acollar slot 62. The semi-cylindrical wall bottom end 48 and the arcuatewall portions 54 and 56 form a bottom tubular wall 64 slotted with thekeyhole slot 52 and the collar slot 62. The slotted tubular wall 64defines a generally tubular cavity 66 extending along a first axis A1.The tubular cavity 66 is adapted for receiving the head 32 of the stapes26 during implantation.

Opposite parallel walls 68 and 70 extend tangentially from thesemi-cylindrical wall 44 and are connected thereto by respective bridges72 and 74. Top rear corners 69 and 71 are rounded. The walls 68 and 70have respective lower edges 76 and 78 spaced above the respectivearcuate wall portions 54 and 56 to define spacer slots 80 and 82. Theopposite parallel walls 68 and 70 have inwardly extending, spaced apartflanges 84 and 86 to define an elongate slot 88 therebetween. Theopposite parallel walls 68 and 70 are spaced from the semi-cylindricalwall 44 above the respective bridges 72 and 74 to define respectivefront slots 90 and 92.

The semi-cylindrical wall 44 at the top end 46 and the side walls 68 and70 form a generally U-shaped wall 94 defining an elongate cavity 96extending along a second axis A2 substantially perpendicular to an axisA1 for receiving an incus 24. As is apparent, the elongate cavity 96 isopen from the top or rear for receiving an incus 24 with the incus 24resting on the flanges 84 and 86. As is apparent, the orientation of theelongate cavity 96 is generally perpendicular to the tubular cavity 66owing to the conventional relationship in orientation between the incus24 and stapes head 32.

In accordance with the invention, the body 42 is of one piececonstruction of a deformable or crimpable (i.e., malleable) metalcapable of retaining different shapes. In one exemplary embodiment ofthe invention, the ISJ prosthesis 40 is formed of an unalloyed titaniumfor surgical implant applications. For example, the prosthesis 40 may bemade of a titanium that satisfies the specifications of AFTM standardF67. This standard identifies four grades of unalloyed titanium forsurgical implant applications. The grades are numbered 1, 2, 3 and 4.The grades range from 1 which is a relatively soft titanium that isreadily malleable to grade 4 which is relatively hard and morespring-like. Advantageously, the prosthesis 40 is made of a grade 2titanium to be malleable. As is apparent, it could be made of othergrades, most particularly grades 1 or 3 according to an amount ofmalleability desired. Moreover, as discussed further below, theprosthesis 40 can be manufactured from a shape memory material. The massand weight of the prosthesis 40 is greatly reduced when compared toceramic ISJ prostheses. The rounded geometry allows reconnection of theISJ without introducing sharp edge interference for surroundingstructures and bone.

In an exemplary embodiment to the invention, the prosthesis 40 has afront to rear dimension of about 2.5 mm and a height of about 2.0 mm,and a width of about 1.27 mm. The tubular cavity 66 may have a radius onthe order of 0.5 mm. The elongate cavity 96 may have a height of about1.27 mm, width of about 1.0 mm and length, not including the space abovethe tubular cavity 66 of about 1.5 mm. The wall thickness is generallyuniform and may be on the order of 0.1 mm. The prosthesis 40 may beformed by machining or the like. As is apparent, the dimensions of theprosthesis 40 could be different from that described herein according tothe needs within the medical community.

The prosthesis 40 is less likely to be displaced because it can beadjusted and/or crimped to the adjoined bones. Particularly, theelongate cavity 96 is adjustable for receiving a portion of the incus24, as shown in FIG. 8. The elongate cavity 96 is adjustable owing tothe malleability of the titanium. Also, the top slots 90, 92 and theelongate slot 88 allow the elongate cavity 96 to be adjusted to fitdifferent diameters of the incus 24. Particularly, the side walls 68 and70 can be deformed above the flanges 84 and 86 owing to use of the frontslots 90, 92. Likewise, the side walls 68 and 70 can be moved closertogether by collapsing the sides of the elongate slot 88. The spacerslots 80 and 82, the collar slot 62 and the keyhole slot 52 allow thetubular cavity 66 to be adjusted to fit the head 32 of the stapes 26.

As described, the size and shapes of the cavities 66 and 96 can beadjusted prior to or after placement on the stapes 26 and incus 24, asshown in FIG. 8. Additionally, the prosthesis 40 can be crimped to thebones of the incus 24 and stapes 26 using a forceps to tighten theconnection. When the prosthesis is made from a shape memory material,the prostheses will be deformed by application of a signal such as heatafter placement on the stapes and incus. The prosthesis 40 does not relyon compression between the malleus 22, the incus 24 and stapes 26 tohold the prosthesis in place until soft tissue encapsulation helpsstabilize the prosthesis to adjoining bones. Nevertheless, growth ofbone tissue will further stabilize the prosthesis 40 as the surface ofthe titanium body 42 may provide a scaffold for on growth.

Thus, in accordance with the one embodiment of the invention, there isprovided an adjustable ISJ prosthesis.

FIGS. 9-12 illustrate an ISJ prosthesis 100 according to a secondembodiment of the invention. The ISJ prosthesis 100 differs from the ISJprosthesis 40, discussed above, in that its design is more particularlyadapted for “self-crimping”. The ISJ prosthesis 100 is manufactured of aunitary body of a shape memory material. The shape memory material maybe a shape memory alloy, such as Nitinol, or a shape memory polymer,such as Calo-MER (The Polymer Technology Group, Berkeley, Calif.). Withsuch a shape memory material, a portion of a prosthesis body can bedeformed into an open configuration to provide spacing to allow theprosthesis to be placed over one or more bones, and when heat is appliedto the prosthesis, the prosthesis self closes to lock around the bonestructure.

Nitinol is a shape memory alloy that has proven biocompatibility. It canbe manufactured via established means. The “memory” of the material isset while the material is in its martensitic phase. During this “shapesetting operation” the in situlfinal geometry of the prosthesis isestablished such that it will grasp the ossicle(s). After the shapesetting operation, the geometry of the prosthesis is altered, i.e.,deformed into the open configuration, in order to allow the prosthesisto be placed easily on the ossicle(s). This temporary or as shippedgeometry is preferably maintained by packaging the prosthesis with ablocking member in the shape set cavity(s) such that the geometry changecan not be initiated during storage or transit. Intraoperatively, asignal such as heat is applied in order to initiate the transformationof the prosthesis microstructure from martensite to austenite. Thismaterial phase transition causes the prosthesis to revert to its shapeset “closed” and final geometry.

The user friendliness, functionality, and stability of several ossicularreplacement devices can be improved by manufacturing them from a shapememory material. Examples of these devices include but are not limitedto incudostapedial joints (ISJ) prosthetics, angular pistons, totalossicular replacement prostheses (TORPs) and partial ossicularreplacement prostheses (PORPs).

The ISJ prosthesis 100 is preferably manufactured of a one piecedeformable body 102 of a shape memory material. The body 102 comprises agenerally cylindrical wall 104 having a generally planar bottom end 106and an angled top end 108. The cylindrical wall 104 defines a generallytubular cavity 110 for receiving a head of a stapes. Rounded notches 112are provided at opposite sides of the bottom end 106 for receiving thearches of a stapes. An elongate longitudinal slot 114 is provided at afront portion of the cylindrical wall 104 between the ends 106 and 108.

A second cylindrical wall 116 extends transversely from the firstcylindrical wall 104 proximate the top end 108. The second cylindricalwall 116 defines an elongate cavity 118 for receiving an incus 24. Asemi-cylindrical bridge 120 connects the second cylindrical wall 116 tothe first cylindrical wall 104 at the top end 108. A pair of axiallyspaced transverse slots 122 are provided in the bottom half of thesecond cylindrical wall 116. A longitudinal slot 124 is provided at alowermost part of the second cylindrical wall 116. The slots 122 and 124define three fingers 126 on each of opposite sides of the longitudinalslot 124.

The ISJ prosthesis 100 is preferably formed by machining a single part.The ISJ prosthesis 100 is illustrated in both its machined condition andshape set condition in FIGS. 9-12. FIGS. 13-16 illustrate the ISJprosthesis 100 deformed for packaging and implantation. Particularly,the first cylindrical wall 104 is opened at the slot 114 as shown at Ato form arms 104A, to expose and enlarge the tubular cavity 100.Similarly, the fingers 126 are spread apart as shown at B to enlarge theelongate cavity 118 for packaging and implantation. Prior to surgery,the deformed ISJ prosthesis 110, see FIGS. 13-16, is placed so that thestapes head 32 is received in the opened tubular cavity 110 and theincus 24 is received in the opened elongate cavity 118.Intraoperatively, the shape memory of the ISJ prosthesis 100 isactivated such that the fingers 126 close to grasp the incus and thearms 104A grab the stapes head by returning to the position shown inFIGS. 9-12, thereby reconnecting the incus to the stapes and allowingfor the transmission of sound vibration through the ossicles to thestructures of the inner ear.

FIG. 17 illustrates a middle ear prosthesis in the form of an angularpiston 200. The angular piston 200 is formed of a unitary body of ashape memory material. The angular piston 200 comprises an elongate rodor piston 202. Extending transversely from the piston 202 is acylindrical wall 204 defining an elongate cavity 206. The cylindricalwall 204 is generally similar to the second cylindrical wall 116,discussed above relative to the ISJ prosthesis 100. In the illustratedembodiment, the cylindrical wall 204 includes a single slot 208transverse to the axis and a longitudinal slot 210 to define oppositearms 212 on either side.

The angular piston 200 is shown in the machined and shaped set form. Thearms 212 can be deformed, similar to that discussed above relative tothe ISJ prosthesis 100, for implantation. The angular piston 200 is usedto replace the stapes. The incus is captured in the elongate cavity 206and the piston or rod 202 is received in a hole in the foot plate oroval window, as is well known. Intraoperatively, the shape memoryproperty of the angular piston 200 is activated, such as by heat, sothat the arms 212 grasp the incus to allow for transmission of soundvibration through the ossicles to the structures of the inner ear. Aswill be apparent, the rod 202 could be of a different material than thecylindrical wall 204 and the components be secured together by any knownmeans. It is also appreciated that a straight stapes piston can beconstructed in a similar manner, such as the slotted bucket stapesprostheses described in U.S. Ser. No. 11/428,672 and U.S. Pat. No.7,087,081, both incorporated by reference herein, wherein the slottedbucket can be made from malleable or shape memory materials.

Shape memory materials can also be used to manufacture total ossicularreplacement prostheses (TORPs) and partial ossicular replacementprostheses (PORPs). FIGS. 18 and 19 illustrate an adjustable length PORPprosthesis 300. The prosthesis 300 permits length adjustment usingstructure generally similar to that described in U.S. Pat. No.6,168,625, owned by the assignee of the present application, and thespecification of which is hereby incorporated by reference herein.

The prosthesis 300 has a head 301 longitudinally displaceable on a shaft302, as in the '625 patent. A “cup” 304 formed of a shape memorymaterial is connected to the shaft 302, opposite the head 301. The cup304 comprises a cylindrical wall 306 closed by a top wall 308 at one endand connecting to a conical wall 310 at a lower end. Preferably roundednotches 312 are provided in diametrically opposite sides of the conicalwall 312. The cylindrical wall 306 includes a longitudinal slot 314opening into one of the rounded notches 32. A transverse slot 316perpendicular to the longitudinal slot 314 is provided just below thetop wall 308. The cylindrical wall 306 defines a tubular cavity 318 forreceiving the head or capitulum of a stapes. The adjustable lengthprosthesis 300 is illustrated with the cup 304 in the machined or closedconfiguration in FIGS. 18 and 19. FIG. 20 illustrates the cup 304 in theshape set position, described below. FIG. 21 illustrates the adjustablelength prosthesis 300 deformed for packaging. The cup 304 is opened byspreading the cup 304 apart at the slot 314 to form arms 306A. Thelength of the prosthesis 300 can then be adjusted by moving the head 301along the shaft 302 and removing the portion of the shaft that extendsbeyond the head. The opened cup 304, see FIG. 21, is positioned over thehead of the stapes. The shape memory material is activated such that thecup 304 returns to the closed shape set position shown in FIG. 20, withthe arms 306A closing to grasp or otherwise retain the stapes headthereby reconnecting the stapes to the ear drum for transmission ofsound vibration to the structures of the inner ear.

FIG. 22 illustrates an adjustable length prosthesis 320, similar to theprosthesis 300 of FIG. 18, with the head removed, according to analternative embodiment of the invention. In this embodiment, theprosthesis 320 includes a shaft 322 and a cup 324. The cup does not openas in the embodiment 304, above. Instead, a tab 326 is provided forlocking the arch of a stapes when received in rounded notches 328. Thetab 326 is shown in the shape set position in FIG. 22. FIG. 23illustrates the tab 326 deformed for packaging. During the operation,the stapes head is received in the cup 324, with the arches resting inthe notches 328. The shaped memory material is heat activated such thatthe tab 326 returns to the position of FIG. 22, extends through thestapes arch and under the capitulum of the stapes dead to grasp andretain the stapes.

There have been described and illustrated herein several embodiments ofossicular prostheses. While particular embodiments of the invention havebeen described, including ISJs, angular pistons, and PORPs, it is notintended that the invention be limited thereto, as it is intended thatthe invention be as broad in scope as the art will allow and that thespecification be read likewise. Thus, while particular specific shapememory materials have been disclosed, it will be appreciated that othersuitable shape memory materials, both metallic and polymeric can be usedas well. In addition, slots have been disclosed so as to definestructure which can deform in accord with the invention, it isappreciated that the term ‘slot’ or ‘slots’, while including the shownstraight linear voids, should not be limited to voids between elementswhich have straight or parallel opposing sides. As such, a slot may bedefined by structure having one or more curvilinear sides, or the slotmay be defined by material having sides obliquely angled relative toeach other. The essence of slot, for purposes of the application, is anarrow void separating two structural elements such that in view of suchvoid, at least one of the structural elements can be deformed relativeto the other into an open position to facilitate access to an anatomicalstructure and/or into a closed position to retain an anatomicalstructure. While several exemplar embodiments including such structuralelements and slot(s) have been described, it is appreciated that otherembodiments may be constructed as well. Furthermore, while machining isdescribed for manufacturing several embodiments, it is recognized thatsuch machining may be via any suitable process including laser cutting,EDM, drills and blades, etc. Also, the prostheses, and individualportions thereof, may be made by means other than or in addition tomachining, including molding. It will therefore be appreciated by thoseskilled in the art that yet other modifications could be made to theprovided invention without deviating from its scope as claimed.

We claim:
 1. A middle ear prosthesis comprising: a unitary body ofdeformable shape memory material capable of retaining different shapes,the body comprising a wall at least partially defining a cavity forreceiving a bone of the middle ear, the wall including at least one slotand being deformable proximate said at least one slot between an openposition for receiving the bone and a closed position, wherein the bodyis reshaped to grasp the bone; and a shaft coupled to the body andextending coaxial with the cavity.
 2. The middle ear prosthesis of claim1 wherein the body is of Nitinol.
 3. The middle ear prosthesis of claim1 wherein the body is of a shape memory polymer.
 4. The middle earprosthesis according to claim 1, further comprising a disc-like headcoupled to said shaft, said head for placement against the tympanicmembrane and located opposite said body.
 5. The middle ear prosthesis ofclaim 1 wherein the body comprises a cup and the wall comprises agenerally cylindrical sidewall closed by a top wall to define the cup,the shaft extending from the top wall and the slot extendslongitudinally in the sidewall and wherein the cup is spread apart atthe slot to open the cup to the open position.
 6. The middle earprosthesis of claim 5 further comprising a transverse slot in thesidewall extending from and perpendicular to the longitudinallyextending slot.
 7. The middle ear prosthesis of claim 6 wherein thetransverse slot is just below the top wall.
 8. The middle ear prosthesisof claim 1 wherein the body comprises a cup and the wall comprises agenerally cylindrical sidewall closed by a top wall to define the cup,and the at least one slot comprises a pair of notches in opposite sidesof the sidewall.
 9. The middle ear prosthesis of claim 8 wherein thebody further comprises a tab extending from the sidewall and the tab isspaced from one of the notches in the open position and partially closesthe one of the notches in the closed position to capture a bone therein.10. An ossicular prosthesis, comprising: a body defining a cavity havingan axis and sized to receive a portion of an ossicle, said bodyincluding at least one slot at which the cavity can be deformed into anopen position to facilitate receiving the ossicle, and a shaft extendingfrom the body, the prosthesis being of unitary construction.
 11. Anossicular prosthesis according to claim 10, wherein said prosthesis ismade from a shape memory material and can be activated intraoperativelyto assume a shape memory position in which the body grasps a portion ofan ossicle.
 12. The ossicular prosthesis according to claim 10, furthercomprising a disc-like head coupled to said shaft, said head forplacement against the tympanic membrane and located opposite said body.13. The ossicular prosthesis of claim 10 wherein the body comprises agenerally cylindrical sidewall closed by a top wall to define a cup, theshaft extending from the top wall and the slot extends longitudinally inthe sidewall and wherein the cup is spread apart at the slot to open thecup to the open position.
 14. The ossicular prosthesis of claim 10wherein the body comprises a cup and the wall comprises a generallycylindrical sidewall closed by a top wall to define the cup, and the atleast one slot comprises a pair of notches in opposite sides of thesidewall.
 15. The ossicular prosthesis of claim 14 wherein the bodyfurther comprises a tab extending from the sidewall and the tab isspaced from one of the notches in the open position and partially closesthe one of the notches in the closed position to capture a bone therein.16. An adjustable length ossicular prosthesis comprising: a head formedof a bioactive or bioinert material configured for contacting a tympanicmembrane when implanted in a human ear, the head including a throughopening; a flexible sleeve mounted to the head at the through opening,the flexible sleeve including a through opening coaxial with the headthrough opening; an elongate shaft having a near end extending throughthe sleeve through opening and the head through opening, the flexiblesleeve through opening being adapted to grip the shaft under staticconditions but permit the shaft to move axially to adjust shaft length;and a cup associated with a distal end of the shaft for receiving a boneof a stapes when implanted in a human ear, the cup comprising a unitarybody of deformable shape memory material capable of retaining differentshapes including a generally cylindrical sidewall closed by a top wall,the sidewall including at least one slot and being deformable proximatesaid at least one slot between an open position for receiving the stapesbone and a closed position, wherein the body is reshaped to grasp thestapes bone.
 17. The adjustable length ossicular prosthesis of claim 16wherein the body is of Nitinol.
 18. The adjustable length ossicularprosthesis of claim 16 wherein the body is of a shape memory polymer.19. The adjustable length ossicular prosthesis of claim 16 wherein afirst slot extends longitudinally in the sidewall and a second slotextends from and is perpendicular to the first slot wherein the cup isspread apart at the slots to open the cup to the open position.
 20. Theadjustable length ossicular prosthesis of claim 16 wherein the at leastone slot comprises a pair of notches in opposite sides of the sidewalland further comprising a tab extending from the sidewall and the tab isspaced from one of the notches in the open position and partially closesthe one of the notches in the closed position to capture a bone therein.